1. Field of the Invention
The present invention relates to a multi-chip structure, and more particularly, to a multi-chip structure with improved heat dissipation capacity.
2. Description of Related Art
As electronic technologies continue to evolve and develop, the trend of integrated circuit (IC) development is to move toward higher level integration, higher device density and smaller volume so that lighter and more compact electronic products are produced. In the semiconductor packaging technologies, developing a high density package structure is always the goal. One example is the development of multi-chip package structure. Accordingly, how to increase the heat dissipation efficiency of a high-density package structure has gradually become one of the major concerns.
FIG. 1 is a perspective view of a conventional package structure. The conventional package structure 100 has been disclosed in U.S. Patent Application No. 2004/0173898. The package structure 100 includes a chip 110, a substrate 120, a plurality of bonding wires 130 and a metal sheet 140. The chip 110 is electrically connected to the substrate 120 through the bonding wires 130 and the metal sheet 140 is disposed between the chip 110 and the substrate 120. When the chip 110 operates and produces heat, the metal sheet 140 transfers the heat to the surrounding. However, the package structure 100 is rather bulky because the metal sheet 140 is disposed between the chip 110 and the substrate 120.
FIG. 2 is a side view of another conventional package structure. The conventional package structure 200 has been disclosed in U.S. Patent Application No. 2006/0060963. The package structure 200 is a multi-chip package structure having two chips 210, two substrates 220, a plurality of bumps 230, a heat spreader 240 and a plurality of stiffening members 250. The heat spreader 240 is disposed between the back surfaces 212 of the two chips 210 and the active surface 214 of each chip 210 faces one of the substrates 220. The chips 210 are electrically connected to their corresponding substrates 220 through the bumps 230. The stiffening members 250 are used for fixing the substrates 220 relative to each other. However, the package structure 200 is rather bulky because the heat spreader 240 is disposed between the back surfaces 212 of the two chips 210.
FIG. 3 is a side view of yet another conventional package structure. The conventional package structure 300 is a multi-chip package structure having two chips 310, a plurality of bumps 320 and an underfill layer 330. The chips 310 are electrically connected to each other through the bumps 320. However, the underfill layer 320 has low thermal conductivity. Hence, the temperature in the area between the chips 310 may rise too high when the chips 310 inside the package structure 300 operate.